U.S. patent application number 13/657400 was filed with the patent office on 2013-05-02 for safety latch lock.
This patent application is currently assigned to FORUM US, INC.. The applicant listed for this patent is Forum Us, Inc.. Invention is credited to Lawrence E. Childress, II, Jeremy S. Granger.
Application Number | 20130104367 13/657400 |
Document ID | / |
Family ID | 48170901 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130104367 |
Kind Code |
A1 |
Childress, II; Lawrence E. ;
et al. |
May 2, 2013 |
SAFETY LATCH LOCK
Abstract
Embodiments of the invention relate to apparatus and methods for
a secondary safety device for use on elevators utilized to move
casing, tubing, sucker rods, or other circular tools or members in
the oil and gas industry. In one embodiment, a secondary latch lock
mechanism for an elevator having a primary safety latch is
provided. The secondary latch lock mechanism comprises a base
portion that is fixed to a body of the elevator, and a handle
movably fixed to the base portion and a first gear device by a
biasing member, wherein the handle is movable to a first position
proximate to the primary safety latch and a second position that is
spaced away from the primary safety latch.
Inventors: |
Childress, II; Lawrence E.;
(Lafayette, LA) ; Granger; Jeremy S.; (Crowley,
LA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Forum Us, Inc.; |
Houston |
TX |
US |
|
|
Assignee: |
FORUM US, INC.
Houston
TX
|
Family ID: |
48170901 |
Appl. No.: |
13/657400 |
Filed: |
October 22, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61553773 |
Oct 31, 2011 |
|
|
|
Current U.S.
Class: |
29/428 ;
403/322.4 |
Current CPC
Class: |
Y10T 29/49826 20150115;
E21B 41/0021 20130101; E21B 19/06 20130101; Y10T 403/595
20150115 |
Class at
Publication: |
29/428 ;
403/322.4 |
International
Class: |
E21B 19/07 20060101
E21B019/07 |
Claims
1. A secondary latch lock mechanism for an elevator having a
primary safety latch, the secondary latch lock mechanism
comprising: a base portion that is fixed to a body of the elevator;
and a handle movably fixed to the base portion and a first gear
device by a biasing member, wherein the handle is movable to a
first position proximate to the primary safety latch and a second
position that is spaced away from the primary safety latch.
2. The secondary latch lock mechanism of claim 1, wherein the first
gear device prevents movement of the handle from the first position
to the second position.
3. The secondary latch lock mechanism of claim 2, wherein the first
gear device comprises a plurality of teeth.
4. The secondary latch lock mechanism of claim 3, wherein the
handle includes a pin that is biased against a portion of the
plurality of teeth in the first position.
5. The secondary latch lock mechanism of claim 2, wherein the
handle comprises a first end and a second end, and the second end
comprises a protruded portion that prevents movement of the primary
safety latch when the handle is in the first position.
6. The secondary latch lock mechanism of claim 2, further
comprising: a second gear device coupled to the handle.
7. The secondary latch lock mechanism of claim 6, wherein the
second gear device comprises a sprocket and a pin.
8. The secondary latch lock mechanism of claim 7, wherein the
sprocket includes a plurality of holes that selectively engage with
the pin.
9. The secondary latch lock mechanism of claim 7, wherein the
second gear device comprises a striker mechanism that selectively
engages with the sprocket.
10. A secondary latch lock mechanism for an elevator having a
primary safety latch, the secondary latch lock mechanism
comprising: a base portion that is fixed to a body of the elevator;
and a handle movably fixed to the base portion, wherein the handle
is selectively engaged with a first gear device disposed on a first
side of the base portion, and a second gear device disposed on an
opposing second side of the base portion.
11. The secondary latch lock mechanism of claim 10, wherein the
handle is movable to a first position proximate to the primary
safety latch and a second position that is spaced away from the
primary safety latch, and the first gear device prevents movement
of the handle from the first position to the second position.
12. The secondary latch lock mechanism of claim 11, wherein the
second gear device comprises a striker mechanism.
13. The secondary latch lock mechanism of claim 12, wherein the
striker mechanism is free to move away from the sprocket when the
handle is in the second position.
14. The secondary latch lock mechanism of claim 13, wherein the
striker mechanism engages the sprocket during movement of the
primary safety latch toward the body of the elevator.
15. The secondary latch lock mechanism of claim 13, wherein the
sprocket is engaged with a pin that is coupled to the handle, and
the handle is moved to the first position during movement of the
primary safety latch toward the body of the elevator.
16. A method for selectively securing a primary safety latch
coupled to an elevator, the method comprising: moving the primary
safety latch from an open position to a closed position; moving a
handle coupled to the elevator to a first position proximate a
first surface of the primary safety latch, the first position
preventing the primary safety latch from moving to the open
position; and moving the handle to a second position that is spaced
away from the first surface of the primary safety latch, the second
position allowing movement of the primary safety latch to the open
position.
17. The method of claim 16, wherein moving the handle to the first
position comprises rotating the handle.
18. The method of claim 16, wherein moving the handle to the second
position comprises lifting and rotating the handle.
19. The method of claim 16, wherein moving the primary safety latch
from the open position to the closed position rotates the handle to
the first position.
20. The method of claim 16, wherein the handle is coupled to a
sprocket that is selectively engaged with a striker device, and
during movement of the primary safety latch from the open position
to the closed position, a second surface of the primary safety
latch contacts the striker device.
21. The method of claim 20, wherein contact of the striker device
with the sprocket causes rotation of the sprocket.
22. The method of claim 21, wherein handle is coupled to the
sprocket, and the handle rotates with the sprocket to the first
position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional Patent
Application Ser. No. 61/553,773, filed Oct. 31, 2011, which is
hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the invention generally relate to methods and
apparatus for improving safety features of equipment used in the
oil and gas industry. More specifically, embodiments of the
invention relate to a secondary safety device for use on elevators
utilized to move casing, tubing, sucker rods, or other tubular
members and/or circular tools, in the oil and gas industry.
[0004] 2. Description of the Related Art
[0005] An elevator is a device that is used to clamp or grip
tubular members or circular tools, such as casing, tubing, drill
pipe, or sucker rods, utilized in a drilling operation or rig
work-over operation. A conventional elevator includes two
arc-shaped members that are hingedly coupled on one end to open and
close in a clamshell manner. The members may be closed to define a
center hole that receives the circular tool, and opened to allow
the circular tool to move into or out of the center hole. In the
closed position, a primary safety latch is used to secure the free
ends of the two arc-shaped members thereby preventing the two
arc-shaped members from opening unexpectedly.
[0006] Primary safety latches on conventional elevators typically
utilize a secondary safety mechanism to prevent the primary safety
latch from opening accidently. The secondary safety mechanism may
include a pin, such as a rod or a large cotter pin, that may be
inserted into a hole or holes that cross the primary safety latch
and prevent the primary safety latch from opening. When the
elevator is to be opened, the pin is removed from the holes, which
allows the primary safety latch to be positioned to allow the
arc-shaped members to open.
[0007] The conventional secondary safety mechanism design has at
least the following drawbacks. Use of the secondary safety
mechanism typically requires the use of two hands to properly align
the holes and install the pin into the holes. The hole/pin
alignment and installation process may extend the time needed to
properly secure the primary safety latch. Additionally, a hazardous
condition is created as the operator has both hands in proximity to
pinch points associated with the elevator. Further, the pin must be
safely stored when not in use. Some conventional elevators include
a storage hole for the pin. However, inserting the pin into the
storage hole adds additional operator time. Other conventional
elevators utilize a cable or small chain attached to the pin to
prevent loss of the pin when not in use. However, the cable or
chain may be damaged and the pin may be lost. Additionally, the
cable or chain securing the pin may create a hazardous condition by
potentially snagging or otherwise injuring an operator.
[0008] What is needed is an improved secondary safety lock
mechanism for safely and efficiently locking a primary safety
latch.
SUMMARY OF THE INVENTION
[0009] Embodiments of the present invention address the issues with
conventional secondary safety mechanisms by providing a secondary
latch lock mechanism that is integrated onto the elevator. The
inventive secondary latch lock mechanism as described herein may be
operated with one hand and is coupled to the elevator, which
prevents loss of the secondary latch lock mechanism as well as
providing additional safety to personnel.
[0010] In one embodiment, a secondary latch lock mechanism for an
elevator having a primary safety latch is provided. The secondary
latch lock mechanism comprises a base portion that is fixed to a
body of the elevator, and a handle movably fixed to the base
portion and a first gear device by a biasing member, wherein the
handle is movable to a first position proximate to the primary
safety latch and a second position that is spaced away from the
primary safety latch.
[0011] In another embodiment, a secondary latch lock mechanism for
an elevator having a primary safety latch is provided. The
secondary latch lock mechanism comprises a base portion that is
fixed to a body of the elevator, and a handle movably fixed to the
base portion, wherein the handle is selectively engaged with a
first gear device disposed on a first side of the base portion, and
a second gear device disposed on an opposing second side of the
base portion.
[0012] In another embodiment, a method for selectively securing a
primary safety latch coupled to an elevator is provided. The method
comprises moving the primary safety latch from an open position to
a closed position, moving a handle coupled to the elevator to a
first position proximate a first surface of the primary safety
latch, the first position preventing the primary safety latch from
moving to the open position, and moving the handle to a second
position that is spaced away from the first surface of the primary
safety latch, the second position allowing movement of the primary
safety latch to the open position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] So that the manner in which the above recited aspects of the
invention can be understood in detail, a more particular
description of embodiments of the invention, briefly summarized
above, may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0014] FIG. 1 is an isometric view of an elevator having a
secondary latch lock mechanism according to embodiments of the
invention.
[0015] FIG. 2 is an isometric view of the secondary latch lock
mechanism of FIG. 1.
[0016] FIG. 3A is an isometric view of a primary latch mechanism
and the secondary latch lock mechanism of FIG. 2 in a closed
position.
[0017] FIG. 3B is a top view of the primary latch mechanism and the
secondary latch lock mechanism of FIG. 3A.
[0018] FIG. 4A is an isometric view of the primary latch mechanism
in a closed position and the secondary latch lock mechanism of FIG.
2 in an open position.
[0019] FIG. 4B is a top view of the primary latch mechanism and the
secondary latch lock mechanism of FIG. 4A.
[0020] FIG. 5 is an exploded view of the secondary latch lock
mechanism of FIGS. 2-4B.
[0021] FIGS. 6A and 6B are schematic views depicting another
embodiment of a secondary latch lock mechanism that may be utilized
with the elevator of FIG. 1.
[0022] FIGS. 7A-8B are various views to describe an opening
sequence of the secondary latch lock mechanism of FIGS. 6A and
6B.
[0023] FIG. 9 is an isometric view of one embodiment of a striker
device that may be used with the secondary latch lock mechanism
shown in FIGS. 6A-8B.
[0024] FIG. 10 is an isometric view of one embodiment of a housing
that may be used with the secondary latch lock mechanism shown in
FIGS. 6A-8B.
[0025] FIG. 11 is an isometric view of one embodiment of the
striker device of FIG. 9 assembled in the housing of FIG. 10.
[0026] FIG. 12 is an isometric bottom view of the secondary latch
lock mechanism of FIGS. 6A-8B.
[0027] FIG. 13 is an isometric view of the secondary latch lock
mechanism of FIG. 12 during closing of a latch plate.
[0028] FIG. 14 is an isometric view of one embodiment of a
secondary latch lock assembly that may be used with the elevator of
FIG. 1.
[0029] FIGS. 15A-15C are bottom views of the secondary latch lock
assembly of FIG. 14 depicting a latch opening sequence.
[0030] FIGS. 15D-15E are bottom views of the secondary latch lock
assembly of FIG. 14 depicting a latch closing sequence.
[0031] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is also contemplated that
elements and features of one embodiment may be beneficially
incorporated on other embodiments without further recitation.
DETAILED DESCRIPTION
[0032] FIG. 1 is an isometric view of an elevator 100 showing one
embodiment of the invention. The elevator 100 includes a body 105
having two members 110A and 1108 that are coupled at one end by a
hinge device 112. The body 105 includes two hooks 114 adapted to
receive a bail that is coupled to a travelling block (both are not
shown). The member 1108 may be configured as a door 115 that may be
closed, as shown in FIG. 1, to define a center hole 116 that clamps
a tool (not shown), such as casing, tubing, drill pipe, or sucker
rods, utilized in a drilling operation or rig work-over operation.
The door 115 may be selectively opened to allow passage of the tool
into and out of the center hole 116 of the elevator 100.
[0033] In the closed position, the door 115 is secured by a primary
latch mechanism 120. The primary latch mechanism 120 comprises a
latch plate 125 that is positioned proximate to one or more
wedge-shaped latch members 128 in the closed position. The latch
members 128 may be formed on the member 1108. The latch plate 125
is secured to the member 110A by a hinge device 130. One or more
support members 132 may be used to couple the latch plate 125 to
the hinge device 130. The hinge device 130 allows the latch plate
125 to move in an arc relative to the member 110A and toward and
away from the member 1108. However, as shown in FIG. 1, the latch
plate 125 is prevented from moving by a secondary latch lock
mechanism 135 coupled to the member 1108.
[0034] The secondary latch lock mechanism 135 comprises a handle
140 having a proximal end 142A and an enlarged distal end 142B. The
enlarged distal end 142B may comprise a post-like projection
extending orthogonally from the handle 140. The secondary latch
lock mechanism 135 also includes an indexer or gear device 144 that
selectively locks the handle 140 in a closed position such that the
distal end 142B of the handle 140 is positioned proximate a surface
145 of the latch plate 125 in the closed position. As shown in FIG.
1, the secondary latch lock mechanism 135 prevents the latch plate
125 from moving away from the door 115 (or member 110B) as the
distal end 142B of the handle 140 is in proximity to the surface
145 of the latch plate 125. As will be explained in greater detail
below, the handle 140 is movable from the closed position to an
open position (not shown) by lifting the handle 140 upwards (Z
direction). Lifting the handle 140 disengages the handle 140 from
the gear device 144 and allows rotation of the handle 140. In
operation, personnel may lift the handle 140 with one hand, which
disengages the handle from the gear device 144, and the handle 140
may be rotated away from the latch plate 125. When the distal end
142B of the handle 140 is clear of the latch plate 125, the latch
plate 125 may be moved away from the door 115 and the door 115 may
be opened.
[0035] FIG. 2 is an isometric view of the secondary latch lock
mechanism 135 of FIG. 1. The handle 140 is coupled to a base 200.
The base 200 may be coupled to the door 115 (shown in FIG. 1) by
fasteners, such as screws or bolts, welding, or other suitable
fastening method. The handle 140 includes a body 205 having an
opening formed in the proximal end 142A that receives a spindle
210. One or both of the handle and the spindle 210 may be coupled
with the gear device 144. The distal end 142B also includes a
protruded portion 215 that extends from the body 205. The protruded
portion 215 may include a flat face 218 that faces the proximal end
142A. The flat face 218 may be substantially normal (i.e., about 85
degrees to about 95 degrees) to the longitudinal axis of the body
205. The body 205 may also include a gripping feature 220, such as
a raised rib or a depressed channel, formed in the body 205 to
assist gripping of the handle 140 during opening and/or closing
operations.
[0036] FIG. 3A is an isometric view of the primary latch mechanism
120 and the secondary latch lock mechanism 135 in a closed
position. FIG. 3B is a top view of the primary latch mechanism 120
and the secondary latch lock mechanism 135 in the closed position.
FIG. 4A is an isometric view of the primary latch mechanism 120 in
a closed position and the secondary latch lock mechanism 135 in an
open position. FIG. 4B is a top view of the primary latch mechanism
120 in a closed position and the secondary latch lock mechanism 135
in the open position. As shown in FIGS. 4A and 4B, the latch plate
125 may be free to move relative to the door 115 when the handle
140 is in the open position.
[0037] FIG. 5 is an exploded view of the secondary latch lock
mechanism 135 of FIGS. 1-4B. A gear device 144 is shown on the base
200. The gear device 144 comprises a plurality of teeth that
selectively engage with a pin 505 that is disposed in the proximal
end 142A of the handle 140. An opening 510 formed in the proximal
end 142A of the handle 140 is sized to receive an outer surface 515
of the gear device 144 as well as a spindle, which may comprise a
fastener 520. The fastener 520 includes a first end 550A and a
second end 550B. The first end 550A may include an enlarged head
portion to prevent the fastener 520 from completely going through
the opening 510 in the handle 140. The fastener 520 includes an
outside dimension that fits within an opening 525 of the gear
device 144. The pin 505 is secured to the handle 140 by an opening
530 formed substantially normal to the axis of the opening 510 in
the proximal end 142A of the handle 140. The pin 505 is also
secured to the fastener 520 at a first through-hole 535 formed
proximate the first end 550A substantially normal to a longitudinal
axis of the fastener 520. A region 540 of the pin 505 is received
in the first through-hole 535 of the fastener 520 when assembled.
Regions of the pin 505 outside of the region 540 are exposed to
upper surfaces (i.e., toothed portions) the gear device 144 on
opposing sides of the fastener 520 when assembled. A retainer
device 545 may be coupled to the second end 550B of the fastener
520. A biasing member 555, such as a spring, may be positioned
between the retainer device 545 and the bottom surface of the gear
device 144. The biasing member 555 is utilized to maintain a
tensional force on the fastener 520, and ultimately the handle 140,
to facilitate engagement of the pin 505 and the gear device 144.
The second end 550B of the fastener 520 may be threaded to
facilitate attachment of the retainer device 545 thereon.
Alternatively or additionally, a pin 560 may be received in a
second through-hole 565 formed proximate the second end 550B and
substantially normal to a longitudinal axis of the fastener 520 in
order to secure the retainer device 545 to the fastener 520. The
secondary latch lock mechanism 135 may also include a lubricating
port 570, which may comprise internal fluid distribution channels
(not shown) and a grease fitting 575 for facilitating lubrication
of the secondary latch lock mechanism 135.
[0038] In one aspect, when the secondary latch lock mechanism 135
is assembled, teeth 580 of the gear device 144 engage the regions
of the pin 505 to prevent movement of the handle 140 in a first
direction A (i.e., a counterclockwise direction) while the handle
140 is biased toward the base 200 by the biasing member 555. Thus,
the force of the biasing member 555 must be overcome by lifting the
handle 140 relative to the base 200 (in the Z direction) to move
the handle 140 from a closed position as shown in FIGS. 3A and 3B
to an open position as shown in FIGS. 4A and 4B. The gear device
144 may also engage the pin 505 to prevent movement of the handle
in a second direction B (i.e., a clockwise direction) in a similar
manner. However, the gear device 144 may be configured to rotate
with minimal lifting force applied to the handle 140 in at least
one direction. For example, the teeth 580 of the gear device 144
may be configured to allow the handle 140 to rotate in the second
direction B with minimal to no lifting force applied to the handle
140. In this example, second direction B may be a closed position
and the gear device 144 is configured to allow the handle 140 to be
easily rotated to the closed position. However, the gear device 144
may be configured to limit movement from the closed position to the
open position (i.e., limit movement in the first direction A),
requiring the handle to be positively lifted and rotated by
personnel before disengagement with the teeth 580 of the gear
device 144.
[0039] FIGS. 6A and 6B are schematic views depicting another
embodiment of a secondary latch lock mechanism 135. In this
embodiment, an automated safety latch lock mechanism 600 is used in
conjunction with the secondary latch lock mechanism 135 described
in FIGS. 1-5. FIG. 6A is a side view of the automated safety latch
lock 600 and FIG. 6B an isometric bottom view of the automated
safety latch lock mechanism 600. The automated safety latch lock
600 is shown in a closed position in both of FIGS. 6A and 6B.
[0040] The automated safety latch lock 600 comprises a sprocket 605
that is coupled to a housing 608 (shown in phantom in FIG. 6A) that
is coupled to the door 115. The housing 608 maintains the sprocket
605 in a stable position relative to the door 115 while allowing
the sprocket 605 to rotate. The sprocket 605 is coupled to the
handle 140 by a lower gear 610 having a pin 612 that selectively
engages holes 614A-614D formed in the sprocket 605. In FIG. 6B, the
pin 612 is disposed in a first hole 614A. A striker device 615 is
coupled to the housing 608 (not shown in FIG. 6B) that the sprocket
605 is mounted to. The striker device 615 includes a movable pin
620 that engages teeth of the sprocket 605. FIGS. 7A-8B follow to
describe an opening sequence of the secondary latch lock mechanism
135 according to this embodiment.
[0041] FIG. 7A is a side view of the secondary latch lock mechanism
135 having the automated safety latch lock 600 shown in FIGS. 6A
and 6B. FIG. 7B is an isometric view of the automated safety latch
lock 600 of FIG. 7A. The housing 608 is not shown in these views in
order to more clearly show the sprocket 605. As shown in FIGS. 7A
and 7B, the handle 140 is lifted (in the Z direction), which raises
the gear 610 relative to the sprocket 605. The gear 610 is moved
relative to the sprocket 605 to a position that removes the pin 612
from engagement with holes in the sprocket 605. In particular, the
pin 612 is raised out of engagement with hole 614A of the sprocket
605. During the raising of the handle 140, the sprocket 605 is
stationary due to a bias against the sprocket 605 provided by the
movable pin 620. When the handle 140 is raised and the pin 612 is
disengaged from the hole 614A, the handle 140, the lower gear 610,
the pin 612, and the retainer device 545 may be rotated relative to
the sprocket 605 which remains stationary during this process.
[0042] FIGS. 8A and 8B show the handle 140 rotated to an open or
unlocked position. The handle 140 may be turned in a
counterclockwise direction until the pin 612 is aligned with a
second hole 614B on the sprocket 605. Lifting of the handle 140
during this rotation is not required and the pin 612 remains biased
toward a surface of the sprocket 605 by the biasing member 555
(shown in FIG. 5). During the rotation of the handle 140, and
portions coupled thereto, such as the lower gear 610, the pin 612,
and the retainer device 545, the sprocket 605 remains stationary.
About a 90 degree rotation of the handle 140 allows the pin 612 to
be reengaged with the sprocket 605, but in a second hole 614B of
the sprocket 605, as shown in FIG. 8B.
[0043] FIG. 9 is an isometric view of one embodiment of a striker
device 615 that may be used with the secondary latch lock mechanism
135 shown in FIGS. 6A-8B. The striker device 615 includes an
opening 900 for the movable pin 620. A biasing member 905, such as
a spring, may be disposed in a body 910 of the striker device 615
to bias the movable pin 620 outward of the body 910 (i.e., in the X
direction). The striker device 615 also includes one or more
indexing features 915 that are configured as a structure
facilitating linear movement of the body 910. The indexing features
915 may be in the form of a protruded shoulder configured to mate
with another structure in the housing 608 (not shown) to facilitate
linear movement of the striker device 615 relative to the housing
608.
[0044] FIG. 10 is an isometric view of one embodiment of a housing
608 that may be used with the secondary latch lock mechanism 135
shown in FIGS. 6A-8B. The housing 608 includes an axle 1000 having
a spindle 1005 that facilitates retention of the sprocket 605
(shown in FIGS. 6A-8B). The housing 608 may also include a recess
1010 having one or more channels 1015 that mate with indexing
features 915 of the striker device 615 (shown in FIG. 9). A biasing
member 1020, such as a spring, may be coupled to a wall 1025 of the
housing 608. The biasing member 1020 is utilized to bias the body
910 of the striker device 615 (shown in FIG. 9) in the Y direction.
FIG. 11 is an isometric view of one embodiment of the striker
device 615 of FIG. 9 assembled in the housing 608 of FIG. 10.
[0045] FIG. 12 shows the secondary latch lock mechanism 135 in an
open position and the latch plate 125 moved a distance away from
the door 115. The striker device 615 is coupled to the housing 608
(not shown for clarity) that allows lateral movement of the striker
device 615 relative to the sprocket 605. In this opened (unlatched)
position, the sprocket 605 and handle 140 (not seen in this view)
do not move. Movement of the latch plate 125 away from the door 115
allows the striker device 615 to move laterally (in a direction
toward the latch plate 125 (in the Y direction)). The movable pin
620 moves past teeth of the sprocket 605 during this lateral
movement of the striker device 615 due to the shape of the teeth.
The movable pin 620 is coupled to a biasing member 905 (shown in
FIG. 9) that biases the movable pin 620 toward the sprocket 605. In
the position shown in FIG. 12, the movable pin 620 is fully
extended. In this position, the latch plate 125 may be opened and
the door 115 may be opened for entry or exit of circular tools. The
secondary latch lock mechanism 135 and the striker device 615 (via
the housing 608 (not shown)) stays coupled to the door 115 during
loading or unloading. The opening process requires only lifting and
rotation of the handle 140, which may be accomplished with one
hand. Further, all parts of the secondary latch lock mechanism 135
are securely coupled to the door 115, requiring no removal of parts
which are stored or otherwise bothersome to personnel. Further, the
position of the striker device 615 shown in FIG. 12 is readied for
closing which is explained in FIG. 13.
[0046] FIG. 13 is an isometric view of the secondary latch lock
mechanism 135 during closing of the latch plate 125. During
closing, an inner surface 1300 of the latch plate 125 contacts a
side 1305 of the striker device 615, which causes the striker
device 615 to move laterally away from the latch plate 125 (in the
Y direction). This causes the movable pin 620 to engage a tooth of
the sprocket 605 and turn the sprocket 605 in a counterclockwise
direction. As the sprocket 605 is engaged with the pin 612, and the
pin 612 is coupled to the handle 140 via the lower gear 610 and the
retainer device 545, the handle 140 is caused to rotate in a
counterclockwise direction in a position that hinders movement of
the latch plate 125.
[0047] FIG. 14 is an isometric view of one embodiment of a
secondary latch lock assembly 1400 that may be used with the
elevator 100 of FIG. 1. The assembly 1400 incorporates the housing
608 and the base 200 of the secondary latch lock mechanism 135 as
an integral unit that may be coupled to the elevator 100 (not
shown) by fasteners (also not shown).
[0048] FIGS. 15A-15C are bottom views of the secondary latch lock
assembly 1400 depicting a latch opening sequence. FIGS. 15D-15E are
bottom views of the secondary latch lock assembly 1400 depicting a
latch closing sequence.
[0049] FIG. 15A shows the latch plate 125 in a locked position. In
this position, the handle 140 is engaged with the gear device 144
(shown in FIGS. 1-5) and secures the latch plate 125 to the door
(not shown). The movable pin 620 is engaged with a tooth of the
sprocket 605. The movable pin 620 is biased against the sprocket
605 by a biasing member (not shown) disposed in the striker device
615. The pin 612, which moves linearly (in the Z direction) as well
as rotationally based on movement of the handle 140, is engaged
with the first hole 614A in the sprocket 605.
[0050] FIG. 15B shows the position of the handle 140 that has been
lifted and rotated counterclockwise approximately 90 degrees. This
allows the latch plate 125 to move away from the secondary latch
lock mechanism 135. As the latch plate 125 is moved away, the
striker device 615 moves in the X direction, which allows the
movable pin 620 to slide relative to the sprocket 605 based on the
shape of the teeth of the sprocket 605. Movement of the handle 140
also causes the pin 612 to disengage from the first hole 614A and
engage the second hole 614B of the sprocket 605.
[0051] FIG. 15C shows the latch plate 125 moved further away from
the automated safety latch lock 600. The striker device 615 is
fully extended from the housing 608. In this position, the striker
device 615 may contact a stop (not shown) coupled to the housing
608, which prevents the striker device 615 from moving too far out
of the housing 608. As shown in FIG. 15C, the movable pin 620 is
fully extended from the body of the striker device 615 and is in
position to engage a tooth of the sprocket 605 to facilitate
reengagement of the secondary latch lock mechanism 135 during a
closing sequence.
[0052] FIG. 15D shows the secondary latch lock assembly 1400 in a
position to reengage the handle 140 during a closing sequence. As
the latch plate 125 is moved in the X direction toward the striker
device 615 during a closing sequence, the inner surface 1300 of the
latch plate 125 contacts the side 1305 of the striker device 615.
Movement of the latch plate 125 in the X direction causes the
striker device 615 to move in the X direction. As the striker
device 615 moves in the X direction, the movable pin 620 contacts a
tooth of the sprocket 605. Continued movement of the striker device
615 causes the sprocket 605 to rotate counterclockwise. As the
handle 140 is coupled to the sprocket 605 by the pin 612 disposed
in the second hole 614B, the handle 140 will rotate
counterclockwise.
[0053] FIG. 15E shows the secondary latch lock assembly 1400 in the
closed position. In this position, the pin 612 is engaged with the
second hole 614B of the sprocket 605. During a subsequent opening
sequence as described in FIG. 15B, the pin 612 will disengage with
the second hole 614B of the sprocket 605 and engage with a third
hole 614C of the sprocket 605 based on movement of the handle
140.
[0054] Embodiments of the secondary latch lock mechanism 135
described herein provide a secure fastening means for safely
locking a latch plate 125 of an elevator. The secondary latch lock
mechanism 135 requires one-handed operation which frees the
operators other hand to perform other tasks. The secondary latch
lock mechanism 135 does not have parts (e.g. pins) that may be lost
or require chains or cables as a fastening means to the elevator,
which may cause injuries or other accidents. As the handle 140 of
the secondary latch lock mechanism 135 as described herein is more
clearly seen by the operator in position over the latch plate 125,
the secondary latch lock mechanism 135 also adds value as a
positive visual indicator to the operator that the latch plate 125
is locked (e.g., as opposed to pins that may be used in
conventional latch locks that may be hard for an operator to see).
Embodiments of the secondary latch lock mechanism 135 also include
an automated closing feature which further increases the efficient
operation of the elevator as well as providing additional safety to
personnel.
[0055] While the foregoing is directed to embodiments of the
invention, other and further embodiments of the invention may be
devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
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